A breathalyzer is simply a machine which can often malfunction or even break down.

Alfonso Gambone
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A Philadelphia criminal defense lawyer representing accused persons throughout Pennsylvania and New Jersey.

Our law firm defends many individuals charged with drunk driving (driving under the influence-DUI) within the Commonwealth of Pennsylvania, specifically Philadelphia, Montgomery, Chester, Delaware, and Bucks County.  A DUI can happen to anyone.  In many of these cases, accused individuals are administered a breathalyzer following their arrest. I have written a number of articles on DUI/DWI focused on strategies within New Jersey and Pennsylvania, along with a free book, this article focuses specifically on 4 ways to challenge a breath test in PA.

Machines Make Mistakes!

Most people wrongly believe  that any breath test which reveals an alleged blood alcohol concentration (BAC) above the legal limit will result in a conviction. This is simply not the case and it’s important to keep in mind that a breathalyzer is simply a machine which can often malfunction or even break down.





There are 4 ways to challenge a breathalyzer:


1.The maintenance and calibration of the device.

2.Test administration.

3.The accuracy of the measurement.

4.Physical Attributes and Presentation of the Accused




If the breathalyzer isn’t maintained to proper calibrations then the results won’t be accurate. Calibration is the process of testing the machine using a simulator solution which has a known alcohol concentration. It is very important that your attorney review the maintenance records of the machine to determine any calibration issues. The prosecution must establish that the breath test has been conducted in accordance with the rules which include preventative maintenance and a certification of the machines accuracy or it leaves open the door for a defense challenge regarding the test’s validity. 



A qualified operator must administer the test. This operator must have completed a course in breath analysis and be trained to operate the type of machine that is being used for testing. While it is sometimes rare to have a breath operator who isn’t qualified at all, it isn’t unusual for a breath operator to use a model on which they have not received the proper certification or training.


Under the umbrella of test administration, one of the most common errors is the failure of the police to observe the person tested for a required time period. In Pennsylvania the observation period is 20 minutes. The purpose of the observation is to ensure that the person tested didn’t insert anything in his or her mouth or regurgitate or vomit before the test. Any of these bodily movements can potentially cause major contamination of the breath sample as they can bring alcohol rich gases up from the stomach, deposit them into the mouth creating what is known as “mouth alcohol”. Mouth alcohol distorts breath alcohol test results. Breathalyzers test deep lung air and not alcohol originating in the mouth. Deep lung air derives from an area within the body which more accurately reflects the alcohol in the blood. Most mouth alcohol will dissipate within 15 minutes and therefore, the observation period must be continuous to ensure that mouth alcohol does not contaminate the sample.



 Most states require 2 breath tests with results within +/- .02% of each other. If your breath test was .09, your criminal defense lawyer can argue that the results are within a margin of error of being under the perceived value. That means that the .09 BAC can be as high as .11 or as low as .07.




Your attorney should not only focus on machine testing procedures but your physical attributes which could possibly produce a falsely high breath test result. Here are some potential problems which could falsely elevate your BAC:


  1. Hyperventilation and blowing too hard on the device
  2. Abnormal body temperature
  3. Abnormal red blood count
  4. Medical conditions such as Gastroesophagial reflux disease (GERD), heartburn, diabetes, and liver disease
  5. Diet
  6. Inhalation of air bag dust which is then exhaled into the machine following a crash 


For more information of drunk driving charges strategies I encourage you to keep reading this blog and visit my free download section.  

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